{
\def\sym#1{\ifmmode^{#1}\else\(^{#1}\)\fi}
\begin{tabular}{l*{4}{c}}
\hline\hline
                    &\multicolumn{1}{c}{\specialcell{\;\;\;\; Arsenic \\ contamination \\ \;\;\;\; (WHO \\ \;\; threshold)}}&\multicolumn{1}{c}{\specialcell{\;\;\;\;\;Arsenic \\ contamination \\ (Bangladeshi \\ \;\; threshold)}}&\multicolumn{1}{c}{\specialcell{\;\;\;\; Arsenic \\ contamination \\ \;\;\;\;\; level}}&\multicolumn{1}{c}{\specialcell{\;\;\;\; Fecal \\ contamination \\ \;\;\;\;\;}}\\\cmidrule(lr){2-2}\cmidrule(lr){3-3}\cmidrule(lr){4-4}\cmidrule(lr){5-5}
                    &\multicolumn{1}{c}{(1)}   &\multicolumn{1}{c}{(2)}   &\multicolumn{1}{c}{(3)}   &\multicolumn{1}{c}{(4)}   \\
\hline
Treated x post      &      -0.011   &       0.005   &       5.007   &      -0.009   \\
                    &     (0.020)   &     (0.018)   &     (3.632)   &     (0.018)   \\
Post                &      -0.063***&      -0.012   &       7.817***&      -0.110***\\
                    &     (0.016)   &     (0.015)   &     (2.853)   &     (0.015)   \\
\hline
R$^2$               &        0.06   &        0.03   &        0.11   &        0.09   \\
N                   &       12026   &       12026   &       12026   &       11684   \\
\hline\hline
\end{tabular}
}
